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  <title>Return the ReadPreference for the Manager</title>
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  <div id="layout-content"><div id="mongodb-driver-manager.getreadpreference" class="refentry">
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  <h1 class="refname">MongoDB\Driver\Manager::getReadPreference</h1>
  <p class="verinfo">(mongodb &gt;=1.0.0)</p><p class="refpurpose"><span class="refname">MongoDB\Driver\Manager::getReadPreference</span> &mdash; <span class="dc-title">Return the ReadPreference for the Manager</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-mongodb-driver-manager.getreadpreference-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="modifier">final</span> <span class="modifier">public</span> <span class="methodname"><strong>MongoDB\Driver\Manager::getReadPreference</strong></span>(): <span class="type"><a href="class.mongodb-driver-readpreference.html" class="type MongoDB\Driver\ReadPreference">MongoDB\Driver\ReadPreference</a></span></div>

  <p class="para rdfs-comment">
   Returns the <span class="classname"><a href="class.mongodb-driver-readpreference.html" class="classname">MongoDB\Driver\ReadPreference</a></span> for the
   Manager, which is derived from its URI options. This is the default read
   preference for queries and commands executed on the Manager.
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-mongodb-driver-manager.getreadpreference-parameters">
  <h3 class="title">参数</h3>
  <p class="para">此函数没有参数。</p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-mongodb-driver-manager.getreadpreference-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   The <span class="classname"><a href="class.mongodb-driver-readpreference.html" class="classname">MongoDB\Driver\ReadPreference</a></span> for the Manager.
  </p>
 </div>


 <div class="refsect1 errors" id="refsect1-mongodb-driver-manager.getreadpreference-errors">
  <h3 class="title">错误／异常</h3>
  <ul class="simplelist">
   <li class="member">Throws <span class="classname"><a href="class.mongodb-driver-exception-invalidargumentexception.html" class="classname">MongoDB\Driver\Exception\InvalidArgumentException</a></span> on argument parsing errors.</li>
  </ul>
 </div>


 <div class="refsect1 examples" id="refsect1-mongodb-driver-manager.getreadpreference-examples">
  <h3 class="title">范例</h3>
  <div class="example" id="example-1303">
   <p><strong>示例 #1 <span class="function"><strong>MongoDB\Driver\Manager::getReadPreference()</strong></span> example</strong></p>
   <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br />$manager&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">MongoDB</span><span style="color: #007700">\</span><span style="color: #0000BB">Driver</span><span style="color: #007700">\</span><span style="color: #0000BB">Manager</span><span style="color: #007700">(</span><span style="color: #DD0000">'mongodb://localhost:27017'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$manager</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getReadPreference</span><span style="color: #007700">());<br /><br /></span><span style="color: #0000BB">$manager&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">MongoDB</span><span style="color: #007700">\</span><span style="color: #0000BB">Driver</span><span style="color: #007700">\</span><span style="color: #0000BB">Manager</span><span style="color: #007700">(</span><span style="color: #DD0000">'mongodb://localhost:27017/?readPreference=secondaryPreferred&amp;readPreferenceTags=dc:ny,rack:1&amp;readPreferenceTags=dc:ny&amp;readPreferenceTags='</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$manager</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getReadPreference</span><span style="color: #007700">());<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
   </div>

   <div class="example-contents"><p>以上例程的输出类似于：</p></div>
   <div class="example-contents screen">
<div class="cdata"><pre>
object(MongoDB\Driver\ReadPreference)#2 (1) {
  [&quot;mode&quot;]=&gt;
  string(7) &quot;primary&quot;
}
object(MongoDB\Driver\ReadPreference)#1 (2) {
  [&quot;mode&quot;]=&gt;
  string(18) &quot;secondaryPreferred&quot;
  [&quot;tags&quot;]=&gt;
  array(3) {
    [0]=&gt;
    object(stdClass)#3 (2) {
      [&quot;dc&quot;]=&gt;
      string(2) &quot;ny&quot;
      [&quot;rack&quot;]=&gt;
      string(1) &quot;1&quot;
    }
    [1]=&gt;
    object(stdClass)#4 (1) {
      [&quot;dc&quot;]=&gt;
      string(2) &quot;ny&quot;
    }
    [2]=&gt;
    object(stdClass)#5 (0) {
    }
  }
}
</pre></div>
   </div>
  </div>
 </div>


 <div class="refsect1 seealso" id="refsect1-mongodb-driver-manager.getreadpreference-seealso">
  <h3 class="title">参见</h3>
  <ul class="simplelist">
   <li class="member"><span class="classname"><a href="class.mongodb-driver-readpreference.html" class="classname">MongoDB\Driver\ReadPreference</a></span></li>
   <li class="member"><span class="function"><a href="mongodb-driver-manager.construct.html" class="function" rel="rdfs-seeAlso">MongoDB\Driver\Manager::__construct()</a> - Create new MongoDB Manager</span></li>
  </ul>
 </div>


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